German Utility Model registration, DE 20 2010 009 414 U1, discloses a program controlled machine tool which has a machine frame including two side walls extending in the longitudinal direction. A longitudinal slide that can travel in the Y-direction is arranged on these two side walls. A cross slide that can travel in the X-direction is arranged on the front side of the longitudinal slide. The cross slide is made as a flat and relatively wide plate. At the face side of this flat cross slide, a machining unit having a vertical spindle head can travel in the Z-direction. A workpiece table arrangement is arranged between two side walls on a fore-part which is narrower compared to the machine frame, that arrangement containing a rotary swivel table in swivel bridge design for the five-axis machining of workpieces.
Furthermore, German patent application DE 199 18 359 A1 discloses a program controlled machine tool which has a machine bed and a column arranged thereon. On the top side of this column, a cross slide can travel in the X-direction and a console is mounted in a travelling fashion on the front face side of this column as a support of a workpiece table. Below the workpiece table and the table console, the machine bed has a semi-circular front part in the fashion of a floor tray. Only three-axis machining is possible by means of this workpiece table arrangement.
Modern program controlled machine tools for machining metallic workpieces, for example, universal lathe and milling machines and machining centers, are usually designed to carry out several complex machining operations on a workpiece which is to be subjected to three-axis to five-axis machining while clamped. The program controlled five-axis machining of a workpiece increases the output of the respective machine and raises the machining accuracy thereof because reclamping operations of the workpiece, optionally intermediate storage and also positional errors occurring in reclamping, are avoided. In these machines, inter alia, a good accessibility to the workpiece table and to the working area is of essential practical significance for loading the workpiece table with heavy and bulky workpieces. Since from certain weights of several kilograms and corresponding dimensions, workpieces may no longer be placed and clamped manually but only by hoisting means, in particular by cranes, on the workpiece table, a good accessibility of the workpiece table and also of the entire working area is highly significant since the workpiece table is usually loaded with such weighty workpieces by means of cranes. Conventional universal milling machines and machining centers usually have no optimum design with regard to the accessibility of the workpiece table, because the workpiece table usually designed as a swivel rotary structure, is arranged in swiveling fashion in the space between the two side walls of the machine frame. It is not always possible without any problems to load this workpiece table with bulky workpieces by means of cranes or other lifting devices.